3.4 The Oracle VM Guest Additions Daemon

The Oracle VM Guest Additions daemon, ovmd, facilitates a
bi-directional messaging channel between Oracle VM Manager and the guest.
It allows first-boot installation configuration, and is capable of
sending and receiving messages consisting of key-value pairs.

It is possible to send messages via Oracle VM Manager to the Oracle VM Guest Additions
daemon running on any guest, using the
ovm_vmmessage utility that can be installed on
any linux system with access to Oracle VM Manager or on the Oracle VM Manager host
itself. See
Section 2.5, “Using Oracle VM Virtual Machine Messaging” for more information on
using this tool.

It is also possible to use the messaging facility included
directly within the Oracle VM Manager user interface to send messages directly to the
Oracle VM Guest Additions daemon running on any guest. See
Sending Messages to Virtual Machines in the
Oracle VM User's Guide
for more information.

Oracle VM Manager makes use of ovmd in order to obtain
IP addressing information from the guest to include in the the
Oracle VM Manager user interface when displaying detailed virtual machine information.
See Section 3.5, “Displaying the Guest IP Address”.

You can run ovmd directly from the command line
to perform actions outside of ovmd's function
as a daemon or system service. Running ovmd
using the --help parameter provides you
with a breakdown of the options supported when run directly from
the command line:

If you are configuring a virtual machine to act as a template or
if you intend to clone it, you may want to set it up so that at
next boot it behaves as if it is booting for the first time,
thereby prompting for configuration input either by the VM API
or on the virtual machine console. This can be achieved by
running the following commands as root within the virtual
machine:

On next boot, the virtual machine will act as if it is
performing a first-time boot. If you have configured
ovmd to run as a service, you are able to
configure it remotely using the messaging
facility and the ovm-template-config script.

3.4.3 Using the Messaging Channel

This section provides an example of a message exchange between
Oracle VM Manager and a running Oracle Linux virtual machine with Oracle VM
Guest Additions installed. The ovm_vmmessage
tool that is included with Oracle VM Utilities is used to communicate
with the Oracle Linux guest. More information about the messaging
utility can be found in Section 2.5, “Using Oracle VM Virtual Machine Messaging”.

Sending a message from the guest to Oracle VM Manager.

Using ovmd, you send information from within
the virtual machine to your Oracle VM Manager using the following syntax:

# ovmd -p key1=value1

The message appears in the Oracle VM Manager user interface, as a
Virtual Machine API Incoming Message event
for the virtual machine in question. When you expand the event,
the description shows the key-value pair and the date and time
when the information exchange took place.

The message from the guest can also be retrieved via the
Oracle VM Managercommand line utility ovm_vmmessage.
To do so, you query the key and the value is returned in the
response: